This invention relates to devices that sanitize footwear and more particularly to methods and devices for electro-kinetically producing a flow of ionized air containing safe amounts of ozone (O3) into such footwear.
Shoes, boots, socks, and other footwear can too readily take on an unpleasant odor from the wearer""s feet. Indeed, the moist and warm environment within footwear can promote the undesired and unhealthy growth of bacteria or germs. (As used herein, the term footwear will be understood to include shoes, boots, slippers, socks, and the like.)
It is known in the art to attempt to deodorize footwear passively, for example by allowing shoes or the like to air out when not being worn. It is also known to insert a chemical into an empty shoe or boot, naphtha perhaps, to impart an odor that will perhaps dominate the odor from the user""s feet.
However such passive techniques are time consuming and do little or nothing to truly sanitize the footwear. Sanitization can be especially troublesome with children""s shoes because children during play often interchange shoes.
One can attempt to actively produce an air flow in an empty shoe with a small fan, to help deodorize the shoe. However the relatively bulky fan or blade mechanism often blocks air attempting to flow out of the footwear. Further, simply flowing air into a shoe does little to remove the cause of the odor in the shoe, bacteria or germs that can exist on the insole or inner lining of the shoe.
Techniques are known to actively produce an air flow using electro-kinetic techniques, by which electrical power is directly converted into a flow of air without mechanically moving components. One such system is described in U.S. Pat. No. 4,789,801 to Lee (1988), depicted herein in simplified form as FIGS. 1A and 1B. Lee""s system 10 provides a first array of small area (xe2x80x9cminisectionalxe2x80x9d) electrodes 20 is spaced-apart symmetrically from a second array of larger area (xe2x80x9cmaxisectionalxe2x80x9d) electrodes 30, with a high voltage (e.g., 5 KV) pulse generator 40 coupled between the two arrays. Generator 40 outputs high voltage pulses that ionize the air between the arrays, producing an air flow 50 from the minisectional array toward the maxisectional array results. The high voltage field present between the two arrays can release ozone (O3), which can advantageously safely destroy many types of bacteria if excessive quantities of ozone are not released.
Unfortunately, Lee""s tear-shaped maxisectional electrodes are relatively expensive to fabricate, most likely requiring mold-casting or extrusion processes. Further, air flow and ion generation efficiency is not especially high using Lee""s configuration. A Lee-type electrode configuration would be difficult to mass produce economically for use in a device intended to sanitize footwear.
There is a need for a footwear sanitizer that can not produce an air flow within an empty shoe or boot, but can also provide true sanitizing action. Preferably such a device should subject the interior of the footwear to a flow of ions containing ozone, to promote sanitation, in addition to deodorizing the footwear.
The present invention provides such a sanitizing device.
The present invention provides a footwear sanitizer device whose housing includes a central portion and two projecting members that are spaced-apart a distance to permit inserting each member into a shoe (or the like). The projecting members are sized to slide into the length of the shoe.
An electrode assembly is located within the distal portion of each projecting member, each assembly comprising a first and second array of electrodes. A battery-operated ionizer unit with DC battery power supply is contained within the housing. The ionizer unit includes a DC:DC inverter that boosts the battery voltage to high voltage, and a generator that receives the high voltage DC and outputs high voltage, pulses or DC, of perhaps 10 KV peak-to-peak. The high voltage output from the high voltage generator is coupled between the first and second array of electrodes in each electrode assembly. Preferably each first and second array is coupled respectively to the positive and negative output ports of the high voltage generator.
Each electrode assembly preferably is formed using first and second arrays of readily manufacturable electrode types. In one embodiment, the first array comprises wire-like electrodes and the second array comprises xe2x80x9cUxe2x80x9d-shaped electrodes having one or two trailing surfaces. In an even more efficient embodiment, the first array includes at least one pin or cone-like electrode and the second array is an annular washer-like electrode. The electrode assembly may comprise various combinations of the described first and second array electrodes. In the various embodiments, the ratio between effective area of the second array electrodes to the first array electrodes is at least about 20:1.
The high voltage creates an electric field between the first and second electrode arrays to produce an electro-kinetic airflow from the first array toward the second array, the airflow being rich in ions and in ozone (O3). Ambient air enters the device through at least one air intake vent, and ionized air (with ozone) exits the distal region of the projecting members through at least one outlet vent. If desired, a single vent in each projecting member can suffice as both an intake and an outlet vent. Preferably a visual indicator is coupled to the ionizer unit to visually confirm to a user when the unit is ready for ionizing operation, and when ionization is actually occurring.
The projecting members are inserted into footwear and the device is turned on, energizing the ion generator. The interior of the footwear is subjected to an outflow of ionized air containing ozone. The resultant airflow not only electro-kinetically airs out the interior of the footwear, but the ozone-rich ionized air flow sanitizes and deodorizes the interior as well.